[vm] Update dartvm usage text

Closes https://github.com/dart-lang/sdk/pull/61482

GitOrigin-RevId: a14e1c028a3ee1d1e7e675df071e537bc4e19297
Change-Id: I98dbae218495e04695c815da67b825d078b8e37c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449073
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>

runtime/bin/common_options.h

@@ -20,7 +20,7 @@ static void _PrintVersion() {
 // clang-format off
 static void _PrintUsage() {
   Syslog::Print(
-      "Usage: dart [<vm-flags>] <dart-script-file> [<script-arguments>]\n"
+      "Usage: dartvm [<vm-flags>] <dart-script-file> [<script-arguments>]\n"
       "\n"
       "Executes the Dart script <dart-script-file> with "
       "the given list of <script-arguments>.\n"